1. Field of the Invention
The present invention relates to a releasing sheet that is applied to the adhesive portions of adhesive labels or sheets.
2. Description of Related Art
Adhesive labels or sheets, made by applying an adhesive to a first side of a label or sheet backing, are known in the art. The second side of the label or sheet has a printing surface, and a releasing sheet is usually attached to the adhesive side to temporarily cover the adhesive.
Such adhesive labels or sheets may be used with word processors or typewriters to produce labels for files and the like. Desired characters and figures are printed on the printing surface of the label, for instance by a printer connected to a personal computer, the printed adhesive label or sheet is cut to a desired size and shape, and the labels are adhered to objects such as files by peeling off the releasing sheet and pressing the adhesive side of the label against the object.
One known apparatus for producing such labels is disclosed in U.S. Pat. No. 4,983,058. This apparatus laminates together a transparent film tape, with characters or the like printed thereon, and a double-sided elongated adhesive tape having a releasing sheet.
As shown in FIG. 3, the tape printer includes a tape printing unit 20 having a thermal head 21, and a tape cassette 22 that is removably mounted on the tape printing unit 20. In FIG. 3, the tape cassette 22 is shown without its top cover.
The tape cassette 22 houses a tape spool 24, around which a transparent film tape 23 is wound, a ribbon supply spool 26, around which a thermal transfer ribbon 25 is wound with its ink surface facing inward, a ribbon take-up spool 27 for taking up the thermal transfer ribbon 25 withdrawn from the ribbon supply spool 26, a double-sided adhesive tape spool 29, around which is wound a double-sided adhesive tape 28 having substantially the same width as that of the transparent film tape 23 and a releasing sheet adhered to the outward facing side, and an alignment roller 30 for aligning the double-sided adhesive tape 28 with the transparent film tape 23. Each of the above spools is rotatably supported between the top cover (not shown) and a support section (not shown) of the tape cassette.
The thermal head 21 can be inserted into an indented section 31 formed on the tape cassette 22. Moreover, a feed roller 33 and a platen roller 34 which are provided on a support body 32 that is rotatably supported on the tape printing unit 20. The platen roller 34 and feed roller 33 are arranged opposite to the thermal head 21 and the alignment roller 30, respectively. The support body 32 is urged against the tape cassette 22 by an urging member (not shown). The platen roller 34 is pressed against the thermal head 21, whereas the feed roller 33 is pressed against the alignment roller 30.
In the tape printing unit 20 having the above-described construction, the thermal head 21 commences print control upon the depression of a print key (not shown) after desired characters have been input. When the print control starts, the transparent film tape 23 is withdrawn from the spool 24 and fed to the thermal head 21 and the platen roller 34 by means of the alignment roller 30 and the feed roller 33. At the same time, the thermal transfer ribbon 25 is withdrawn from the ribbon supply spool 26 and fed toward the thermal head 21 and the platen roller 34 at the same speed as the transparent film tape 23.
Characters or the like are then printed on the transparent film tape 23 via the thermal transfer ribbon 25 and the thermal head 21 in synchronism with the feeding operation of the transparent film tape 23 and the thermal transfer ribbon 25. The printed film tape 23 is then fed to the alignment roller 30 and the feed roller 33. The double-sided adhesive tape 28 is withdrawn from the double-sided adhesive tape spool 29 by the cooperative action of the alignment roller 30 and the feed roller 33. At this time, a first adhesive surface of the double-sided adhesive tape 28 is aligned with and affixed to the printed surface of the transparent film tape 23. In this way, an adhesive label P is prepared.
However, when printing is carried out using the above described tape printer, the alignment roller 30 and the releasing sheet of the double-sided adhesive tape 28 come into contact with each other. Similarly, when an adhesive label or sheet, as described above, is printed using a typewriter, word processor or a printer, the releasing sheet of the adhesive label or sheet comes into contact with various members such as a platen and feed rollers which are disposed in a traveling path of the typewriter, word processor or printer.
If the releasing sheet of the adhesive labels or tapes described above have a significantly different electrostatic charge pattern than the platen or feed rollers, the probability that static electricity will be generated on the releasing sheet is high. Particularly, if a so-called transfer coating method is employed to form the adhesive labels or tapes. The development of static electricity becomes even more likely during low temperature and low humidity conditions.
In a transfer coating method, an adhesive is first applied to a releasing sheet, the coated sheet is dried, and the dried coated releasing sheet is affixed to a label or tape backing. In such a process, moisture contained in the releasing sheet will be significantly decreased during the drying step as a result of evaporation. This will, in turn, considerably increase the probability of generation of static electricity.
The static electricity generated during the printing tends to cause the adhesive label or tape to adhere to the platen, the feed roller, or the like. As a result, the adhesive label or tape may get caught up in the platen or the feed roller. If this happens, feeding of the label or tape may be affected, and misprinting may occur. It will become impossible to decipher the printed characters or figures due to a deficiency in feed rate. Further, when the printed adhesive label or tape adheres to the printer or the like due to static electricity, handling of the adhesive sheet or label becomes extremely troublesome. Additionally, the resulting charged adhesive label or sheet attracts dirt or dust.
When a rolled double-sided adhesive tape is subjected to continuous printing, as described above, static electricity may sometime accumulate on the tape printer. In the worst case, the accumulated static electricity discharges, resulting in adverse effects such as malfunctioning of electronic components within the tape printer.